PLANT SPOTLIGHT: Black Walnut (Juglans nigra)

Posted on Categories Blog, Cooking & Preservation, Harvesting, Home, Orchard Care, Plant Profiles, Plants, POPharvests, Propagation, Recipes, Tree Care, Wild EdiblesTags , , , , , , , , , , , ,

Black Walnut (Juglans nigra)

Tree Facts

Black Walnut  (Juglans Nigra) is a perennial, stone fruit tree native to Eastern North America, commonly found in riparian zones (area between water and land).  Technically the walnut produces a fruit called a “drupe” and is not a true nut! The drupes are harvested in the fall, dehulled and dried to allow the nut meat to cure for consumption.  This tree can grow very large, eventually reaching over 100’ in height and 6’ in diameter. The black walnut is a member of the Juglandaceae family. Careful consideration should be made before planting or growing around this tree as it is allelopathic, suppressing growth of many other plant species by releasing a chemical called juglone. The black walnut contains the highest concentration of juglone in the nut hulls, roots, and leaves and is commonly used as an herbicide.  This tree has numerous uses, such as: nutritional, medicinal, dye, structural/decorative, antibacterial, and herbicidal.

Seasonal Care-

The black walnut tree grows well between zones 5a-9a.  Commonly found natively near water, these trees prefer deep rich soil, moist yet well drained. Black Walnut is self fertile, but puts on a better fruit set with two trees. It is generally easy to grow with little attention needed.  

Winter/ Spring: Pruning is generally not necessary. Compost or organic fertilizer can be added in the Spring to maximize nut production.

Summer: The first year, a Black Walnut tree should be irrigated every week with 3-5 gallons of water. Once established, the tree generally only needs watering during severe drought.

Fall: Fruit is generally harvested from the ground, dehulled and allowed to dry for a few weeks before cracking the nut and consuming/storing the nut meat.

Nutritional Benefit:

Black Walnuts are packed with nutrients and are considered a superfood.  They contain one of the highest protein contents of any nut (7 grams per serving), as well as high levels of Manganese, Omega-3, antioxidants and other nutrients.  The nutritional content supports metabolism and bone structure, and can help protect against cardiovascular disease, diabetes, and certain neurodegenerative conditions.

Propagating Black Walnut Trees:

As previously noted, Black Walnuts are toxic to a variety of plants and research should be done prior to planting to understand the effects that Black Walnut will have in that area.  Black Walnuts are best propagated by seed, collecting the fruit in the fall dehulling and immediately placing 5-6 whole nuts, 5-6” in the ground. Protect the nuts from animals, by placing chicken wire or cloth over the nuts and securing to the ground.  Cover with leaves/mulch and be sure to properly label location. In the spring remove the protective cover and water the sapling every week with 3-5 gallons of water.

Processing Black Walnuts for Nutmeat

  • Pick nuts up off the ground as soon as possible by hand or nut wizard. It is best to process nuts while the hull is mostly green to avoid mold and astringent nutmeat.
  • Use gloves to handle and de-hull the nuts. They will stain your fingers. They will also stain concrete for a period of time, clothing, and other surfaces.
  • Remember that walnut hulls halve a chemical called “juglone” that suppresses the growth of certain plants, so be mindful of where you take your hulls and wash water
  • Remove green hulls with hammer, knife, or strong hands (some people step on them or even drive over them covered in a tarp!). If hulls are too tough to work, let soften for a few days or buy a de-huller!
  • If you encounter worms when removing hulls, do not be alarmed as they do not affect the nut meat inside the inner shell
  • Rinse de-hulled walnuts to remove debris however you wish. A simple method is to fill a 5-gallon bucket with water and agitate a batch of nuts with a hoe, cement mixer, or by hand three times. Discard nuts that float, a legendary sign of likely spoilage.
  • Spread cleaned nuts out in a single layer to dry for 2-4 weeks. Make sure you do this in an area that squirrels absolutely cannot get to, as they will find a way to steal your nuts. Squirrels broke into Michael’s outdoor solar dehydrator this year because the openings didn’t have thick enough wire mesh! Some people swear that forced heat drying black walnuts at 95-100 deg F for 3-4 days is best for flavor and storage. Turn the shells every so often throughout the drying process.
  • Dried nuts can be stored in shell in a cool, dry location. They can be also be frozen until ready for use. Shelled nuts can be stored in a fridge or freezer for longer shelf life, and salt brining with further dehydration is a way to store walnuts longer at room temperature.
  • To crack black walnuts, do not use a regular nut cracker. It will break. Use a nut cracker that is made for black walnuts, or use a vice grip, or hammer with good hand eye coordination. You’ll want a nut pick or small scraping device to remove the nut meat from the cracked shell.
Volunteers de-husking black walnuts at a POPharvest gleaning workshop at The Woodlands in West Philadelphia.

Black Walnut Recipes!

  1. Basic Black Walnut Pie 
  2. Black Walnut Hummingbird Cake (Cream Cheese Frosting)
  3. Black Walnut Cinnamon Ice Cream
  4. Black Walnut Fudge 
  5. Black Walnut Chicken Quiche 

**Click HERE for more delicious black walnut recipes!!**

Processing Black Walnuts for Dye, Wood Stain, and Ink

  • Add green hulls to a stainless steel pot of water (We used the first rinse water from the above process).
  • Simmer for at least 30 minutes. For darker colors simmer longer, add more hulls, and even boil down the liquid.
  • Cool the liquid and strain through muslin bag or other cloth.
  • Test the strength of the dye/stain/ink. If darker color desired, return to step 2. Be careful not to scorch the liquid if boiling it down.
  • Store liquid in a glass jar or bottle, and add 100 proof vodka or rubbing alcohol (up to 1:4 ratio) to prevent mold and preserve for later use. The liquid will mold after a while if untreated.
  • Experiment with tie-dye or other fabric dying methods, black walnut as a wood stain, and as ink! Fabrics dye a cocoa brown and do not require a pre-mordant for dye to set as with other dyes. Wood stain is a light brown that can me made darker by concentrating the liquid.
Black Walnut tie-dye and wood-staining demos at POPharvest workshop.

Black Walnuts as Medicine

Black walnut hulls contain very powerful medicine that has been used for a variety of conditions including intestinal worms in humans and animals, while it must also be approached with caution. It is also a natural source of iodine. Do not attempt to use black walnut medicine without first consulting professional medical practitioners and clinical herbalists.

This POP Blog was written by 2018 POP Intern Greg Hample and Orchard Director Michael Muehlbauer with assistance from Admin Assistant Natalie Agoos. 

SUPPORT US!  If you found this entry useful, informative, or inspiring, please consider a donation of any size to help POP in planting and supporting community orchards in Philadelphia:

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Plant Spotlight: The Plucky Mulberry (Morus)

Posted on Categories Blog, Harvesting, Home, Plant Profiles, Plants, POPharvests, Propagation, Recipes, Wild EdiblesTags , , , , , , , , ,

Written by 2016 POP Intern, Lucia Kearney. 

Despite their reputation as a weed tree, many people in both urban and rural environments have very fond childhood memories of mulberries!  My own past is filled deliciously with mulberries. When I was a kid, my parents worked in Manayunk. On days when there was no school, I’d go to work with them, and in the summertime I was always happy to see the mulberry tree growing by the parking lot. At their office picnic in Chestnut Hill, there was mulberry tree in the front yard where my brother and scores of other office kids and I would stuff ourselves full of fruit. There was a mulberry tree in our neighbor’s yard when we moved to the suburbs, and mulberry trees by Henderson Field. Needless to say, mulberries are something that I look forward to and thoroughly enjoy every year.

Behold, the wonderful mulberry!
Behold, the wonderful mulberry!


Mulberries are a temperate and subtropical group of trees and shrubs – just walking around Philadelphia, you’re sure to encounter several different species. White or Common Mulberries (Morus alba) originate from China, Black Mulberries (Morus nigra) from Western Asia, Russian Mulberries (Morus alba ‘Tatarica’) from Northern China, and Red Mulberries (Morus rubra) come from the Eastern United States.  Many of the mulberry trees found in the city are wild seedlings that are a cross between White and Red Mulberry species.

Mulberries and people have been pals for a long long time; they actually figure prominently in a Babylonian myth about the tragic lovers Pyramus and Thisbe. In a story of forbidden love very similar to that of Romeo and Juliet, Pyramus and Thisbe, forbidden by their families to marry, agree to meet beneath a mulberry tree. Thisbe arrives first, but flees after seeing a lioness, mouth bloody from a recent kill, accidentally leaving her veil behind. Pyramus, arriving later, sees veil and bloody-mouthed lion and, assuming that Thisbe has been eaten, kills himself. Thisbe returns to the scene to find the body of Pyramus, and kills herself out of grief. Their blood is said to have stained the previously white fruit red.

Thisbe & Pyramus
Thisbe & Pyramus

Mulberries are generally irregularly shaped, bushy-headed trees, with trunks that often lean. Size depends largely on the species – White Mulberries are usually 30 to 50 feet in height and Red Mulberries can reach as high as 70 feet. Black Mulberries tend to be much smaller, occasionally reaching 30 feet in height. Longevity varies as well; while Black Mulberries can bear fruit for hundreds of years, Red Mulberries rarely make it past 75 years. Leaves are alternate, heart-shaped, or lobed, with what looks like serrated edges and pointed tips.

Different Kinds of Mulberry Leaves
Different Kinds of Mulberry Leaves

Flowers often go unnoticed unless you’re looking for them – they are small and feathery and roughly resemble the fruit that they’ll go onto produce. Some varieties are dioecious (meaning that trees are either male or female) while others are monoecious (meaning trees have both male and female parts). Trees are wind-pollinated, no cross-pollination is necessary, and some cultivars will set fruit without any pollination at all.

Flowers from a Red Mulberry Tree
Flowers from a Red Mulberry Tree

Fruits also vary in color, size, and ripening time. Confusingly, the color of the fruit does not reliably identify the species; White Mulberries (in spite of the story of Thisbe and Pyramus) can have white, lavender, or black fruit; Red Mulberries are deep red to almost black, and Black Mulberries are usually large, dark, and juicy. Berries tend to resemble raspberries and blackberries in form, though they are generally longer and narrower. The Himalayan Mulberry – which I’m dying to try – produces berries that can reach several inches in length! White and Red Mulberries ripen in late spring, while Black mulberries ripen in summer to late summer. All mulberries ripen over a period of around six weeks rather than all at once, which is good news for us mulberry lovers.

White and Lavender Mulberries
White Mulberries can bear white, lavender, or even black fruit!
Red Mulberries
Red Mulberry fruit can be red or black.
Black Mulberries
Black Mulberry fruit is usually aptly named!
Morus macroura, also known, amongst other things, as the Himalayan Mulberry
Morus macroura, also known, amongst other things, as the Himalayan Mulberry


Mulberries are actually the sweetest of all fruit!  Fruits can be eaten raw or cooked, and can also be made into wine, cordials, jams, tarts, cobblers, or tossed onto oatmeal or cooked into pancakes. Fruits can also be dried, and made into fruit leather if combined with other, more fibrous fruit. The possibilities are endless; an image search for ‘mulberry recipes’ comes up with dazzling results, I promise you. Be aware that the fruit doesn’t keep long raw – once picked, it should be eaten or cooked within a few days (this is one reason why you don’t generally see mulberries in grocery stores). Also take care while picking black mulberries as their juice will stain hands and clothing (and whatever else you get on them) purple; as such, mulberry juice can also be used as a natural dye. In China, mulberry juice is produced commercially on a large scale and is quite popular; the juice stays fresh for several months without preservatives.

A Black and White Mulberry Ricotta Tart
A Black and White Mulberry Ricotta Tart
Almond and Mulberry Tart
Almond and Mulberry Tart
Mulberry Ice Cream
Mulberry Ice Cream

The leaves – when prepared properly – can also be eaten (please read disclaimer at the bottom of this article before consuming any mulberry leaves). In the Middle East, mulberry leaves are stuffed with ground chicken or lamb. Check out a recipe for chicken stuffed mulberry leaves here. Take note that raw, white mulberry leaves contain toxins that can irritate the stomach and skin, and are said to be slightly hallucinogenic. However, once steamed, the leaves can be safely eaten and used in pies, lasagnas, and salads. Dried mulberry leaf powder – which is high in protein and carbohydrates, and has a distinct, fragrant smell – is used as an additive in buns, bread, cakes, and biscuits in China. A tea can also be made from the dried leaves.

Chicken Stuffed Mulberry Leaves
Chicken Stuffed Mulberry Leaves

Famously, mulberries (usually White Mulberries) are cultivated as food for silkworms; silkworms exclusively eat the leaves of certain species of mulberry (they don’t, for example, eat black mulberries), and in China and Japan, many mulberries are grown solely for this purpose. One of the reasons that White Mulberries and their hybrids are so common in the United States is that they were originally imported to try to start a silk industry in the 1830’s. It takes around 33-40lbs of fresh mulberries to produce just 2.2lbs of fresh cocoon.uses,

 Silkworm Feeding on a Mulberry Leaf + Cocoons

Silkworm Feeding on a Mulberry Leaf + Cocoons

The stems and stem powder are also a good medium for mushroom production; wood ear mushrooms and the medicinal fungus Ganoderma lucidum are produced on mulberry logs or powder.

All parts of the mulberry contain a milky sap that can be used to make a type of rubber, and several species have fibrous bast fibers beneath the bark that can be used to make rope or paper. The wood is a deep yellow, hard, strong, durable, flexible, and coarse grained and is valued for carving, inlays in cabinet work, and for the crafting of musical instruments.

A Bowl Made from Mulberry Wood
A Bowl Made from Mulberry Wood

Birds adore mulberries, so some orchardists plant mulberries as a trap crop to tempt birds away from whatever fruit they’re producing.  In particular, mulberry fruit season overlaps with that of cherries and blueberries, which are the crops most often lost to birds.  Russian mulberries – which are hardier and whose blossoms are not as easily damaged by high winds – are often used as windbreaks.

Nutritional Information/Medicinal Uses

NOTE: The following information has not been evaluated by the Food and Drug Administration. Please read our full edible/medicinal use disclaimer at the end of this article and seek medical advice from a qualified professional before using a new plant in your diet. 

Mulberries are rich in carotene, and in vitamins B1, B2, and C. In fact, one cup of raw mulberries contains 85% of the daily recommended intake of vitamin C! They are also high in iron, vitamin K1, potassium, and vitamin E. Mulberries also contain anthocyanins, a family of antioxidants that may help to lower cholesterol prevent hard disease, and rutin, a powerful antioxidant that may help to protect against cancer, diabetes, and heart disease.

Traditionally, mulberries have been used as a mild laxative. The USDA reports that leaves from the white mulberry tree have been used to treat sore throats, eye infections, and colds. Mulberry leaves are rich in gamma-aminobutylic acid, which is effective in reducing high blood pressure, as well as in alanine, which is useful in easing hangovers. The American Diabetes Association has also noted that mulberry leaves may help to reduce blood sugar levels in people suffering from type-2 diabetes.


Considered by some to be a weed tree, it’s not surprising that mulberries are often disease-free and tend to thrive in challenging conditions and poor soils. All species prefer full sun in cooler climates, but will tolerate partial shade. While mulberries prefer moist soil, they are drought resistant once established, and require little to no fertilization. They are also tolerant of groundcover and can grow well with grass beneath.

There are named varieties of all species of mulberry selected for their fruit quality.  The Philadelphia Orchard Project has primarily planted the variety ‘Illinois Everbearing’, which is known for its large, tasty, seedless fruit and long season of harvest. Although Black Mulberries are the species most commonly grown for their fruit around the world, they are only marginally hardy in Philadelphia (zone 7).  POP is now experimenting with planting some dwarf varieties of Black Mulberry in more protected locations.

Mulberries can also be propagated via seed – which requires 16 weeks of stratification – or by hardwood cuttings made in the winter, grafting/chip budding, layering, or air layering. Some species can also be propagated from softwood cuttings in the summer. Using mycorrhizal fungi spores as a cuttings dip reportedly increases the success rate of propagation.

Young trees should be planted between 25-35ft apart in the spring or fall. Some formative pruning can be done in the first few years to establish a strong 4-5 branch framework; otherwise, pruning should only be done to remove dead or crossing branches. Pruning should be done in the wintertime while trees are dormant. If trees are being used as a windbreak, they should be planted 8-20ft apart, and can withstand clipping if needed. White mulberry leaves can also be grown as a vegetable crop. To do this, trees are planted densely in rows and coppiced annually at a height of 2-3 feet. Fresh leaves can then be picked throughout the growing season.

Coppiced White Mulberries Interplanted with Nitrogen-Fixing Acacias in Las Canadas, Mexico
Coppiced White Mulberries Interplanted with Nitrogen-Fixing Acacias in Las Canadas, Mexico

And so this year let’s give thanks for the hardy and abundant mulberry! I’m looking forward to making many more mulberry memories, and I hope you all are too.

SUPPORT US!  If you found this entry useful, informative, or inspiring, please consider a donation of any size to help POP in planting and supporting community orchards in Philadelphia:


The Philadelphia Orchard Project stresses that you should not consume parts of any wild edible plants, herbs, weeds, trees,​ or bushes until you have verified with your health professional that they are safe for you. As with any new foods that you wish to try, it is best to introduce them slowly into your diet in small amounts.

The information presented on this website is for informational, reference, and educational purposes only and should not be interpreted as a substitute for diagnosis and treatment by a health care professional. Always consult a health care professional or medical doctor when suffering from any health ailment, disease, illness, or injury, or before attempting any traditional or folk remedies. Keep all plants away from children. As with any natural product, they can be toxic if misused.

To the best of our knowledge,​ the information contained herein is accurate and we have endeavored to provide sources for any borrowed​ material. Any testimonials on this web site are based on individual results and do not constitute a warranty of safety or guarantee that you will achieve the same results.

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